Believe it or not, 'ova' is one of those tiny crossword building blocks that shows up with more personality than you'd expect. I see it mostly used in two broad ways: the literal biological sense — eggs, female gametes — and as a neat little abbreviation that constructors lean on when they need three letters that are vowel-heavy and crossword-friendly. In themed puzzles, constructors often use 'ova' as a motif: if the theme is Easter, spring, birds, reproduction, or anything egg-related, 'ova' can be the tidy little revealer or a repeated element stitched into longer theme answers. You'll sometimes find it literally hidden across two words in theme entries (like the letters O‑V‑A spanning a phrase), or placed in circles/rebuses to signify an egg icon in the grid.
Beyond thematic decoration, 'ova' is a solver-friendly fill because it's familiar and uncontroversial, so it gets slipped into the grid to preserve symmetry without drawing attention. Sometimes crossword cluing leans into wordplay: a clue might read 'They develop into embryos' or 'Female reproductive cells,' which points solvers straight to 'OVA.' Other constructors will cheekily clue it by referencing biology class or even fandoms — 'direct-to-video anime releases' is a modern-style clue in puzzles that nod toward pop-culture audiences, giving the same three letters a completely different vibe.
I enjoy spotting the different uses because they reveal the constructor's intent: are they being literal, playful, or trying to bridge science and pop culture? It’s a tiny entry, but it can tell you a lot about the puzzle's personality — and I like that kind of subtlety in a themed grid.